New here but thought I would chime in. Being in Texas we can use any centerfire cartridge for deer. I have used slugs for a hog and it is very effective. This year I used buckshot because it was all I had to use. I was using standard 2 3/4 in 00 buck in 12 gauge. I was using a Mossberg patrol shotgun with 18 1/2 barrel with cylinder bore, no choke. Shot was at 20feet. All nine pellets hit the lungs and the deer dropped, kicked, and went nowhere. Though very effective only 2 of the 9 pellets exited. But at very close range, under 25 yards, buckshot is hard to beat, IMO......